We have investigated the influence of the laser fluence, ambient nitrogen and target material on the synthesis of aluminum nitride nanosized powders by reactive laser ablation. Pure aluminum and aluminum nitride were used as targets. The study revealed that were pure nanosized AlN powders (3-25 nm in diameter) can be synthesized for laser fluences higher than 11 J/cm2(approximately 1.6 GW/cm2). AlN powders were obtained at any nitrogen pressure in case of AlN target, while aluminum target pressure >= 100 Torr was required.